hey I need a condition + rule like this: wheter I go to www.example.com it serves me index.php but otherwise if I go to www.example.com/my-article it points me out to show_post.php?url=$1

I´ve tried this: http://apaste.info/6i2 . Please note RewriteRule ^viewpost-([^/]*)$ show_post.php?url=$1 [L] is just a workaround and not my final intention ( it works when I request www.example.com/viewpost-my-article but my intention is www.example.com/my-article )